//
// (C) Copyright 2009 Irantha Suwandarathna (irantha@gmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 */


using System;

namespace EffiProzDB
{

    /**
     * Represents an SQL view or anonymous subquery (inline virtual table
     * descriptor) nested within an SQL statement. <p>
     *
     * Implements {@link org.hsqldb.lib.ObjectComparator ObjectComparator} to
     * provide the correct order of materialization for nested views / subqueries.
     *
     * @author boucherb@users
     * @author fredt@users
     */
    public  class SubQuery 
    {

        public int level;
        public bool hasParams;
        public bool isResolved;
        public bool isExistsPredicate;
        public bool uniqueRows;
        public Select select;
        public Table table;
        public View view;
        public bool isMaterialised;

        public void populateTable(Session session)
        {

            Result r = select.getResult(session, isExistsPredicate ? 1
                                                                   : 0);

            if (uniqueRows)
            {
                r.removeDuplicates(session, select.iResultLen);
            }

            table.insertResult(session, r);
        }

        /**
         * This results _in the following sort order:
         *
         * view subqueries, then other subqueries
         *
         *    view subqueries:
         *        views sorted by creation order (earlier declaration first)
         *
         *    other subqueries:
         *        subqueries sorted by depth within select query (deep == higher level)
         *
         */
        public static int compare(SubQuery a, SubQuery b)
        {

            SubQuery sqa = (SubQuery)a;
            SubQuery sqb = (SubQuery)b;

            if (sqa.view == null && sqb.view == null)
            {
                return sqb.level - sqa.level;
            }
            else if (sqa.view != null && sqb.view != null)
            {
                Database db = sqa.view.database;
                int ia = db.schemaManager.getTableIndex(sqa.view);
                int ib = db.schemaManager.getTableIndex(sqb.view);

                if (ia == -1)
                {
                    ia = db.schemaManager.getTables(
                        sqa.view.getSchemaName()).Count;
                }

                if (ib == -1)
                {
                    ib = db.schemaManager.getTables(
                        sqb.view.getSchemaName()).Count;
                }

                int diff = ia - ib;

                return diff == 0 ? sqb.level - sqa.level
                                 : diff;
            }
            else
            {
                return sqa.view == null ? 1
                                        : -1;
            }
        }
    }
}